Qualcomm Technologies, Inc. Haptics driver

Haptics peripheral in QTI PMICs can support different type of actuators or
vibrators:
  1) Eccentric Rotation Mass (ERM);
  2) Linear Resonant Actuator (LRA).
This binding document describes the properties for this module.

Properties:

- compatible
  Usage:      required
  Value type: <string>
  Definition: It can be one of the following:
		"qcom,haptics",
		"qcom,pm660-haptics",
		"qcom,pm8150b-haptics".

- reg
  Usage:      required
  Value type: <u32>
  Definition: Base address of haptics peripheral.

- interrupts
  Usage:      required
  Value type: <prop-encoded-array>
  Definition: Peripheral interrupt specifier.

- interrupt-names
  Usage:      required
  Value type: <stringlist>
  Definition: Interrupt names.  This list must match up 1-to-1 with the
		interrupts specified in the 'interrupts' property. Following
		interrupts are required: "hap_play_irq", "hap_sc_irq".

- qcom,actuator-type
  Usage:      optional
  Value type: <string>
  Definition: Specifies the type of the actuator connected on the output of
		haptics module. Allowed values: "erm", "lra". If this is
		not specified, then LRA type will be used by default.

- qcom,vmax-mv
  Usage:      optional
  Value type: <u32>
  Definition: Specifies the maximum allowed output voltage in millivolts
		for the actuator. Value specified here will be rounded
		off to the closest multiple of 116 mV. Allowed values:
		0 to 3596. If this is not specified, then 1800 mV will be
		used by default.

- qcom,play-rate-us
  Usage:      optional
  Value type: <u32>
  Definition: Specifies the period at which each sample of the 8-byte waveform
		registers is played. For ERM, this period is flexible and it
		can be chosen based on the desired shape of the pattern.
		For LRA, it should be set equal to the resonance period
		specified in the LRA actuator datasheet. Allowed values are:
		0 to 20475. If this is not specified, 5715us play rate is used.

- vdd-supply
  Usage:      optional
  Value type: <phandle>
  Definition: Specifies the phandle of the regulator device which supplies
		haptics module through VDD_HAP pin. This is only needed if VDD_HAP
		is supplied from an external boost regulator instead of VPH_PWR.

Following properties are specific only when LRA actuator is used:

- qcom,lra-resonance-sig-shape
  Usage:      optional
  Value type: <string>
  Definition: Specifies the shape of the LRA resonance drive signal. Allowed
		values: "sine", "square". If this is not specified, sinusoid
		resonance driver signal is used.

- qcom,lra-allow-variable-play-rate
  Usage:      optional
  Value type: <empty>
  Definition: If specified, "qcom,wf-play-rate-us" for LRA defined in each
		effect could be different with the resonance period of the
		LRA actuator.

- qcom,lra-auto-resonance-mode
  Usage:      optional
  Value type: <string>
  Definition: Specifies the auto resonance technique for LRA. Allowed values are:
		"zxd": zero crossing based discontinuous method;
		"qwd": quarter wave drive method;

Following properties could be specified in child nodes for defining vibrating
waveforms/effects:

- qcom,effect-id
  Usage:      required
  Value type: <u32>
  Definition: Specifies the effect ID that the client can request to play the
		corresponding waveform defined in this child node. The ID is
		normaly defined and sent from userspace for certain user
		notification event.

- qcom,wf-pattern
  Usage:      optional
  Value type: <prop-encoded-array>
  Definition: Specifies the waveform pattern in a byte array that will be
		played for the effect-id. The bit fields of each byte are:
		 [7]: drive direction, 0 - forward; 1 - reverse
		 [6]: overdrive, 0 -- 1x drive; 1 -- 2x drive
		 [5:1]: waveform amplitude
		 [0]: reserved.

- qcom,wf-vmax-mv
  Usage:      optional
  Value type: <u32>
  Definition: Specifies the maximum allowed output voltage in millivolts
		for this effect. Value specified here will be rounded
		off to the closest multiple of 116 mV. Allowed values:
		0 to 3596. If this is not specified, the value defined in
		"qcom,vmax-mv" will be applied.

- qcom,wf-play-rate-us
  Usage:      optional
  Value type: <u32>
  Definition: Specifies the play period in microseconds for each byte pattern.
		Allowed values are: 0 to 20475. For LRA actuator, if
		"qcom,lra-allow-variable-play-rate" is defined, it could be
		set to other values not equal to the resonance period of the
		LRA actuator.

- qcom,wf-repeat-count
  Usage:      optional
  Value type: <u32>
  Definition: Specifies the repeat times for the waveform pattern. Allowed
		values are: 1, 2, 4, 8, 16, 32, 64, 128.

- qcom,wf-s-repeat-count
  Usage:      optional
  Value type: <u32>
  Definition: Specifies the repeat times for each sample defined in
		qcom,wf-pattern. Allowed values are: 1, 2, 4, 8.

- qcom,wf-brake-pattern
  Usage:      optional
  Value type: <prop-encoded-array>
  Definition: Specifies the brake pattern with 4 elements used to enable the
		internal reverse braking. Allowed values for each element are:
			0: no brake
			1: brake with (Vmax / 2) strength
			2: brake with Vmax strength
			3: brake with (2 * Vmax) strength
		If this property is specified with an array of non-zero values,
		then the brake pattern is applied at the end of the playing
		waveform.

- qcom,lra-auto-resonance-disable
  Usage:      optional
  Value type: <empty>
  Definition: If specified, the hardware feature of LRA auto resonance detection
		is disabled.

- qcom,wf-line-in-audio
  Usage:      optional
  Value type: <empty>
  Definition: Boolean flag to indicate if the effect is playing the audio signal
		comes into LINE-IN pin. If this is specified, the pattern
		specified in "qcom,wf-pattern" will be ignored.

- qcom,wf-line-in-pwm
  Usage:      optional
  Value type: <empty>
  Definition: Boolean flag to indicate if the effect is playing the PWM signal
		comes into LINE-IN pin. If this is specified, the pattern
		specified in "qcom,wf-pattern" will be ignored.
Example:
  qcom,haptics@c000 {
	compatible = "qcom,haptics";
	reg = <0xc000 0x100>;
	interrupts = <0x3 0xc0 0x0 IRQ_TYPE_EDGE_BOTH>,
		     <0x3 0xc0 0x1 IRQ_TYPE_EDGE_BOTH>;
	interrupt-names = "hap-sc-irq", "hap-play-irq";
	qcom,actuator-type = "lra";
	qcom,vmax-mv = <1800>;
	qcom,play-rate-us = <8000>;
	qcom,lra-resonance-sig-shape = "sine";
	qcom,lra-auto-resonance-mode = "qwd";
	qcom,lra-allow-variable-play-rate;

	wf_0 {
		/* CLICK effect */
		qcom,effect-id = <0>;
		qcom,wf-play-rate-us = <6250>;
		qcom,wf-pattern = [3e 3e 3e];
		qcom,lra-auto-resonance-disable;
	};

	wf_5 {
		/* HEAVY_CLICK effect */
		qcom,effect-id = <5>;
		qcom,wf-play-rate-us = <6250>;
		qcom,wf-pattern = [7e 7e 7e];
	};

	wf_6 {
		/* RINGTONE_x effect */
		qcom,effect-id = <6>;
		qcom,wf-line-in-audio;
	};
  };
